1. Field of the Invention
The present invention relates to an electromagnetic valve including a manual operation element that is manually operated to switch a valve member, and a safety device that prevents erroneous operation of the manual operation element.
2. Description of the Related Art
While a typical electromagnetic valve is configured to switch a valve member for switching a flow passage of fluid by the action of electromagnetic force, it includes a manual operation mechanism that allows the valve member to be manually switched during a blackout, in an emergency, or during maintenance. There are push-in type and slide type manual operation mechanisms. In a push-in type, a switch shaft provided in an electromagnetic valve is pushed in by pressing an operating member provided on an outer surface of the electromagnetic valve, thereby switching a valve member. In contrast, in a slide type, a switch shaft is pushed in by an inclined face or the like provided on a lower face of an operating member, which is provided on an outer surface of an electromagnetic valve, by horizontally sliding the operating member along the outer surface, thereby switching the valve member, as disclosed in Patent Literature, Japanese Unexamined Patent Application Publication No. 11-22850. The slide type is easier to handle than the push-in type.
The electromagnetic valve is normally equipped with a safety device that prevents erroneous operation of the operating member. Patent Literature, Japanese Unexamined Patent Application Publication No. 11-22850, discloses a safety device that prevents erroneous operation of an operating member (operating piece) of the slide type. The safety device includes a cover covering the operating piece, and the cover is connected to an electromagnetic valve such as to be turnable about a shaft. When the operating piece is covered with the cover, it cannot be moved. The operating piece can be moved after the cover is opened.